Aw
CZLN6, man, don't let me confuse the boy....
Oh, I think it was an E-string or a 1 amp piece of fuse wire takes a 62.5 thou PVCR down to about 54 thou. If Bill suggests 46 thou, then use the brass inserts he describes, or use two 1 amp fuses wound together...tightly.
1 amp fuse wire is 28.7 thou if its copper. Silver is different, and the formulae for wire diameter changes at various amps due to electrical engineering conventions. I had a scrap of paper I've used for the last 3 months to tune my Holley, but I got the core info off the net, then lost the Excell file for 1, 2, 5, 10, 15 and 30 amps in copper, silver and nickel. I'll try and track it down...
For every 2000 feet increase in altitude, you can roughly reduce the jet size by one Holley call size. There is a much more accurate cc/min conversion, which caters for close limit laboratory style calibration and emissions jets in each call size, but again, the file is gone
No, wait, its here...
http://www.hotrod.com/techarticles/engi ... ewall.html 
And if you use my cc/min chart from the
Jetting for any 2 or 4-bbl Holley, you can use these formulae:-
http://image.hotrod.com/f/15970733+w750 ... uning+.jpg
and
http://image.hotrod.com/f/15970736+w750 ... uning+.jpg
Additional interest:- if you need 93 octane at sea level to run your 11:1 compression Mustang knock free, at 3000 ft, you'll only need 91.5 octane. At 5000 feet, you'll need 90.5. Sadly, there is nowhere with a road on American soil 12000 feet high so you could run 87 octane without knocking...
xctasy":3brwqlfu said:
Some time ago, wsaiii showed how it was done with much more accuracy than I can.
Two power valve channel restrictions for a PN 4412 (and 7448) Holley 2300 series 500 (and 350) CFM are 62.5 thou each. Most PVCR are equal to 8 jet sizes up on a std Holley jet.
Two stock 64 call size jets, plus two 62.5 thou holes, would be a certain amount of total jetting.
If the stock PVCR's should be 53 to 55 thou, then the enough wire must be added to reduce the effective discharge area of two PVCR to 54 thou.
Copper, nickel and iron fuse wire exists in pacakges at stores. If you can track down one piece of 1 amp copper fuse wire, and loop it through the two PVCR holes you'll reduce the total annulus of discharge by two lots of 28.7 thou.
Total PVCR will then be (3.141*(0.0625/2)*(0.0625/2))*2)=0.006134
but less two lots of 28.7 thou diameters (3.141*(0.0287/2)*(0.0287/2))*2)=0.0013, which makes 0.006134-0.0013, or 0.004834.
Total with wsaiii 54 tho PVCR is (3.141*(0.054/2)*(0.054/2))*2)=0.004580
Close enough to get 12.5:1 air fuel
Ok just having a little fun, but I do appreciate all the information (a little more than I can digest in one sitting). I think I’m going to go with the Weber 38, my limited research would indicate the loss of economy will be minimal and my local Yoda seem to like Weber carbs. I have some time since I just got the engine back on the stand last night but I already have the Weber adaptor from C.I. so... That big check I wrote makes me even more determined not to screw this up so I will be taking things slow and one step at a time. My son is coming home this weekend (he wants to get his hands dirty) so the push is to get things painted before Saturday. Even paint color has been mulled over and over and over 
Fat fingered the calculator again... 
